1. Send 2 units of flow along s->a and a->b, and 1 unit along s->b.  Then we have 3 units of flow along b->t, and the value of the flow is 3.

2. No. This is explained in detail in section 7.2.4 of the textbook, but size(any cut) >= size(min cut) = size(max flow) >= size(any flow).